ground

すでにご存じのことかと思いますが，groundの動詞形です。もともとは「船が乗り上げる，座礁する」という意味ですが，飛行機に使われ場合は「駐機する」「地上に足止めになる」という意味ですね。（GP）

Hurricane Sandy grounds thousands of flights worldwide

(CNN) -- Airlines around the world have canceled flights to and from the northeast United States because of the growing threat from deadly Hurricane Sandy.
Middle Eastern, European, Asian and U.S. airlines have grounded flights in and out of America's eastern seaboard as 350-mile wide Sandy prepares to make landfall later Monday.
As Americans brace for the storm, airlines are preparing to take a financial hit, with the weather stranding their passengers in cities across the globe.
"Every day this goes on you're seeing combined losses to the airlines of roughly $10 million," said Simon Calder, travel editor of the UK's The Independent newspaper.
"The cost is actually much worse for European airlines like British Airways and Virgin Atlantic, because they have to pay for accommodation and meals for their customers who are stuck in the U.S. -- particularly in New York."

European Union law says airlines have a "duty of care" to take care of stranded passengers. There is no such law governing U.S. airlines.
"Delta and United can just say, 'Sorry, this is a weather event and you're not covered,'" Calder told CNN.

http://edition.cnn.com/2012/10/29/travel/hurricane-sandy-flight-cancellations/index.html?hpt=hp_t1